Gas turbine engines include compressor rotors with a plurality of rotating compressor blades. Minimizing the leakage of air between tips of the compressor blades and a casing of the gas turbine engine increases the efficiency of the gas turbine engine as the leakage of air over the tips of the compressor blades can cause aerodynamic efficiency losses. To minimize leakage, the gap at tips of the compressor blades is set so small that at certain conditions, the blade tips may rub against and engage an abradable seal on the casing of the gas turbine. The abradability of the seal material prevents damage to the blades while the seal material itself wears to generate an optimized mating surface and thus reduce the leakage of air.
Cantilevered vanes that seal against a rotor shaft are also used for elimination of the air leakage in turbine engines. Current cantilevered vane tip sealing requires that the tip gaps need to be set more open than desired in order to prevent rub interactions that can cause rotor shaft spallation, vane damage or rotor shaft burn through caused by thermal runaway events during rubs. Current materials have been shown to lack the durability to prevent spallation and they lack the abradability to prevent vane damage.